<?php

if (!defined('BASEPATH'))
  exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package		CodeIgniter
 * @author		ExpressionEngine Dev Team
 * @copyright	Copyright (c) 2006 - 2012 EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 2.0
 * @filesource	
 */
// ------------------------------------------------------------------------

/**
 * CodeIgniter Caching Class 
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Core
 * @author		ExpressionEngine Dev Team
 * @link		
 */
class CI_Cache extends CI_Driver_Library {

  protected $valid_drivers = array(
      'cache_apc', 'cache_file', 'cache_memcached', 'cache_dummy'
  );
  protected $_cache_path = NULL;  // Path of cache files (if file-based cache)
  protected $_adapter = 'dummy';
  protected $_backup_driver;

  // ------------------------------------------------------------------------

  /**
   * Constructor
   *
   * @param array
   */
  public function __construct($config = array()) {
    if (!empty($config)) {
      $this->_initialize($config);
    }
  }

  // ------------------------------------------------------------------------

  /**
   * Get 
   *
   * Look for a value in the cache.  If it exists, return the data 
   * if not, return FALSE
   *
   * @param 	string	
   * @return 	mixed		value that is stored/FALSE on failure
   */
  public function get($id) {
    return $this->{$this->_adapter}->get($id);
  }

  // ------------------------------------------------------------------------

  /**
   * Cache Save
   *
   * @param 	string		Unique Key
   * @param 	mixed		Data to store
   * @param 	int			Length of time (in seconds) to cache the data
   *
   * @return 	boolean		true on success/false on failure
   */
  public function save($id, $data, $ttl = 60) {
    return $this->{$this->_adapter}->save($id, $data, $ttl);
  }

  // ------------------------------------------------------------------------

  /**
   * Delete from Cache
   *
   * @param 	mixed		unique identifier of the item in the cache
   * @return 	boolean		true on success/false on failure
   */
  public function delete($id) {
    return $this->{$this->_adapter}->delete($id);
  }

  // ------------------------------------------------------------------------

  /**
   * Clean the cache
   *
   * @return 	boolean		false on failure/true on success
   */
  public function clean() {
    return $this->{$this->_adapter}->clean();
  }

  // ------------------------------------------------------------------------

  /**
   * Cache Info
   *
   * @param 	string		user/filehits
   * @return 	mixed		array on success, false on failure	
   */
  public function cache_info($type = 'user') {
    return $this->{$this->_adapter}->cache_info($type);
  }

  // ------------------------------------------------------------------------

  /**
   * Get Cache Metadata
   *
   * @param 	mixed		key to get cache metadata on
   * @return 	mixed		return value from child method
   */
  public function get_metadata($id) {
    return $this->{$this->_adapter}->get_metadata($id);
  }

  // ------------------------------------------------------------------------

  /**
   * Initialize
   *
   * Initialize class properties based on the configuration array.
   *
   * @param	array 	
   * @return 	void
   */
  private function _initialize($config) {
    $default_config = array(
        'adapter',
        'memcached'
    );

    foreach ($default_config as $key) {
      if (isset($config[$key])) {
        $param = '_' . $key;

        $this->{$param} = $config[$key];
      }
    }

    if (isset($config['backup'])) {
      if (in_array('cache_' . $config['backup'], $this->valid_drivers)) {
        $this->_backup_driver = $config['backup'];
      }
    }
  }

  // ------------------------------------------------------------------------

  /**
   * Is the requested driver supported in this environment?
   *
   * @param 	string	The driver to test.
   * @return 	array
   */
  public function is_supported($driver) {
    static $support = array();

    if (!isset($support[$driver])) {
      $support[$driver] = $this->{$driver}->is_supported();
    }

    return $support[$driver];
  }

  // ------------------------------------------------------------------------

  /**
   * __get()
   *
   * @param 	child
   * @return 	object
   */
  public function __get($child) {
    $obj = parent::__get($child);

    if (!$this->is_supported($child)) {
      $this->_adapter = $this->_backup_driver;
    }

    return $obj;
  }

  // ------------------------------------------------------------------------
}

// End Class

/* End of file Cache.php */
/* Location: ./system/libraries/Cache/Cache.php */